Electric switch



E. D. MOORE ELECTRIC SWITCH July 17, 1934.

Filed Aug. 22

l a 9 S 7 3 C l l l l I I l l n 1 l l l I I I u Invenlor E'DAE D. o of? Patented July 17, 1934 UNITED STATES ELECTRIC SWITCH Edgar D. Moore, Mansfield, Ohio, assignor to The Ohio Brass Company, Mansiield, Ohio, a cor-v poration of New Jersey Application August 22, 1928, Serial No. 301,302

7Claims.

My invention relates to electric switches.

Among the objects of my invention I provide a switch which:

(a) Will open and close a circuit.

(b) Will automatically open the circuit when the current therein suddenly reaches or exceeds a predetermined value.

(c) Will automatically open the circuit upon a sustained current, that is a current of predetermined value flowing through the circuit for a predetermined time.

(d) Will automatically open instantly upon closing the switch if the current flowing equals or exceeds a predetermined value.

(e) Will permit setting automatic trip mechanism in condition to open the switch, prior to closing the switch.

(f) Will have athermal mechanism to control the opening of the switch under `sustained cur- ,o rent.

(g) Will instantly deprive the thremal mechanism of current when the current equals or exceeds a predetermined value.

(h) Can be manually operated as well as automatically operated to the openposition.

(i) Cannot be held closed withthe current ilowing therethrough.

(j) Can be closed under normal operating conditions without danger of automatically opening.

(Ic) Will allow smallamperage protection with delicate thermo element without danger of damage on heavy overloads.

Other objects and advantages of myinvention 35' will appear as I proceed with the disclosure of my invention.

My invention resides in the new andnovel construction, combination and relation of the various parts hereinafter described and shown 40 in the attached drawing.

In the drawing:

Fig. 1 is a top plane view of my switch in the open position with the cover almost entirely broken away.

Fig. 2 is a partial plane view of my switch as shown in Fig. 1 but in the closed position.

Fig. 3 is a side view with the cover broken away with the switch in the 'open position as shown in Fig. 1.

Fig. 4 is a side view of Fig. 1 to show the thermal mechanism.

In the preferred embodiment of my invention I employ a base member 1 preferably of insulating material. Mounted upon thebase are ter- '56 minal posts 2 and 3 which are intended for. connection to a source of power P and P', and terminal posts 4 and 5 which are intended for connection to a translating device Ml such as an electric motor.

Mounted upon the base is an electro-magnetic @o trip E which comprises a soft iron core 6, pole pieces 7 and 8, a pivoted armature 9 with a latch 10 and/two energizing 'coils 11 and 12.

Also mounted upon the base member 1 is a thermal mechanism T comprising a U- or hairpin-shaped member 13 composed of what is known as thermal metal comprising two dissimilar metals of different coeflicients of expansion and which are welded together. The adjacent ends 14 and 15 of the thermal element 70 are rigidly secured to the base 1 but the loop end is free to move and has secured thereto a contact element 16 arranged to contact 'with an adjusting screw 17 mounted in a standard 1 8 flxedly secured to the base by a screw 19.

The thermal element 13 is so placed that ii its temperature is increased above normal, its free end will bend upwardly until iinally the contact 16 will engage with the screw 17. The xed 4ends of the thermal element 13 are connected to the posts 2 and4 by means of the conductors 20 and 21 securedy to the endsiof the thermal member by means of the screws 22 and 23 respectively.

Als'o mounted upon the base 1 is a switch S. The switch comprises a standard 24 held to the base by means of the screws 25 and having uprights 26 and 27. The uprights are provided with registering openings in which is mounted a reciprocating metal rod 28. Mounted fixedly 90 upon the rod 28 is an insulating element 29 held in place by means of a small transverse pin. Secured. to the element 29 is ametal plate 30 which is insulated from the rod 28 and engages with the latch 10 to hold the switch in a closed 95 position. The plate 30 is of metal to avoid wear where the element 29 would engage with the latch 10. Y

Interposed between the upright 26 and the element 29 is a spring 31 tending to move the 10G rod 28 to its open position when the switchv is closed and hold the switch open when in the. open position. v

Rotatably and slidably mounted upon the rod 28 is an insulating handle 32 which bottoms 105 against the end of the rod 28 or substantially so when the switch is open` Secured to the end of the handle 32 and in rotatable relation thereto is a movable bar 33 which moves longitudinally only with the movement oi the handle 32.

The bar 33 has the lower end U-shaped, between relative longitudinal movement.

the legs of which is a ange 34 of the handle 32, thereby locking the handle and bar against The bar is also provided with a bent end 35 arranged to rest against the upright 26 when the switch is in the open position and maintained in that position while open by means of the spring 36Y interposed between the upright 27 and the U-shaped end 37 of the bar 33.

The bar 33 rests close to the edges of the uprights 26 and 27, which prevents the bar 33 from rotating about the axis of the rod 28. Secured to and projecting longitudinally along the rod 33 is an insulating plate 38 secured in place by the rivets or screws 39 and secured to the free end of the plate 38 is an L-shaped metal plate 40 also held by rivets. Engageable contacts 41 and 42 vare secured to the rod 28 and the member 40 respectively and engaged when the switch is closed.

The standard 24 is connected to the terminal 5 by means of the conductor 43, thereby connecting the rod 28 and its contact 41 to the terminal standard 18 by the conductor 45 and the other end is-connected to the free end of the coil 11 andthese ends are connected to the terminal 3 `by means of the conductor 46.

Y The armature 9 lis biased toward the element 29 by'means of the iiat spring 47.

, Mounted 'upon the pole piece 8 is a flat resilient member 48 and an upwardly bent end 49 adapted to engage the end of the armature 9 when the insulating handle 50 is pressed inwardly and thereby pushing the latch 10 out of holding engagement with the plate 30, thus permitting the members 28 and 29 to move under the actionof the spring 31.

When it is desired to close the switch, the member 32is pressed inwardly and simultaneously'the-members 28 and 33 move inwardly and the elements 41 .and 42 maintain their separation. i

When the plate 30 has passed the latch 10,

the handle 32 maybe released which will permit the plate 30 and the rod 28 to remain 4in an position but it is possible to open the switch if desired without operating the automatic trip or amature 9.

As soon as the switch is closed, current will flow from the terminal 2 through the hairpinY 13, to the post 4 and then to and through the translating device to post 5 and the current will then owfrom the terminal 5 through conductors i3-'and 45 and contacts 41 and 42 and conductor 44-and`y coil 11 to the terminal 3. It the translatingdevice should be overloaded such that it cannot start, or should the current drawn thereby exceed a predetermined value, or should there be a short circuit in the device, then the coil 11 will be instantly energized to such an extent that the armature 9 will trip instantly upon the contacts 41 and 42 engaging and thus instantly open the switch. This same action will happen during the operation of the translating device should any unusual conditions take place effecting a sudden flow of current in excess of a predetermined value.

If, after the translating device has been .in operation, the load thereon should be increased gradually until it exceedsA a predetermined amount, the current will likewise increase and during the period ofv increase, this current ilowing through the ther-fnal element 13 will cause the same to heat, which in turn will cause the I) free end to approach the screw 17 and which it will'eventually engage, and when it is so engaged current will then ow through the left leg of the hairpin, through the standard 18, conductor 45 and coil 12, thereby energizing the 95 coil 12 to a degree which willzcause the armature 9 to be attracted and trip the switch S, permitting the same to open.

vWhen the free end of the thermal element 13 engages the screw 17, it throws the coil l2 100 directly across the main incoming leads connected to the terminals 2 and 3, thereby throwing the coil 12 directly across the source of power. The armature 9, however, will act instantly and the switch S will open instantly, 1M thereby preventing injury to the thermal element 13, and the coil..12 is wound withv much finer wire than the coil 11, thereby introducing considerable resistance into the circuit and preventing a large ow of current through the halrpin 13. I

The time for which a givenfiow of current is allowed to take place is controlled by the thermal element 13 and this can be regulated by adjusting the screw 17. Thegreater the space between the contact 16 and screw 17, the greater will be the time that a given current will ow without causing the switch to auton'latically open. By adjusting the screw 17, the amount of overload the translating device may stand for l a given period of time may be varied.`

It will be apparent that with a given' setting 'of the screw 17 with respect to the contact y16,

that the greater the current iiowing through the thermal element'13, the less-will be the 125 time it will ow' before the switch opens and vice versa.

To protect the user from contact with the various live parts of the switch and Ato further maintain the action' of the hairpin constant l or at least unaffected by the surrounding air currents, I enclose the parts with a cover 51 held in place by a screw 52 or other suitable Imeans.

Modifications will suggest `themselves to those skilled in the art after reading the herein lll disclosure, therefore, I wish to be limited on1y` by my claims.

1. An electric switch comprising a pair of independently reciprocating contacts mounted in axial alignment and movable in a straight line and normally in their o'pen position and cooperative to close a circuit, manually operable means to move the contacts from their open position and oneof the contacts movable independently of the operable means while the other contact -is lockecllwithl and movable longitudinally only withthe'op'erable means, means to engage and hold one' Vof the vcontacts when both` contacts separate means biased to move each of the contacts to its open position when the operable` v in their open position and cooperating to close a circuit, the contacts mounted on telescopically arranged members to move therewith, manually operable means to reciprocate the members and contacts in a straight line from their open position and one of the members and its contact movable independently of the operable means while the other member is locked with and is movable only with the operable means, holding means to engage and hold the independently movable member when both members and their contacts have been moved from their open4 position, electrically controlled means to act upon the holding means to release the holding means when the current reaches a predetermined sustained value and separate means biased to move the members and their contacts to their open position when the operable means is released to close the circuit and the. biased means operating until the held member is released and moved to its open position.

3. An electric switch comprising a pair of normally open but independently movable contacts mounted on a pair of elongated members to reciprocate in a straight line and having the contacts axially aligned to cooperate to close a circuit, manually operable means locked with one member and arranged to reciprocate both members in one direction simultaneously, the contacts remaining separated during said movement, releasable means to hold one of the members returning to its open position and means acting to move the other member to its open position when the manually operable means is released and permit the contacts to engage to close the circuit and electrically controlled mechanism to trip the releasable means to release the held member and separate the contacts.

4. An electric switch comprising a pair of normally open but independently movable and insulated contacts mounted on a pair -of elongated and slidable members and having the `contacts axially aligned with each other and with the axis of one member, the second member L the same when the current through the switch reaches a predetermined value and separate means operating on the members to engage the contacts when the rst member is held and to move the members to their original positions and disengage the contacts when the held member is released. v

5. An electric switch comprising a pair of normally separated contacts mounted on separate parallelly disposed elongated members mounted to reciprocate in a straight line, manually operable means mounted on one member to reciprocate relative thereto to move the member in one direction only and spring means to move Vit in the other direction, the manually operable means arranged to move-the other member in one direction and spring means to move the said members and operable means in the other direction, the two members moving in the same direction when the operable means is operated and the contacts remain separated, releasable holding means to prevent one member from returning to its original position when the operable means is released but permitting the other member to move towards its original position until the contacts engage and electrically controlled mechanism to trip the holding means to permit the contacts to separate.

6. An electric switch comprising an elongated reciprocable member, a second elongated member mounted on the first member and arranged to reciprocate relative to the first member, one end of each member provided with a contact arranged to engage and close a circuit but normally disengaged, manually operable means mounted on the first said elongated member and movable relative thereto to move the members and the contacts from their open position and movable only with the other member, means to engage and hold onev member when both members and their contacts have been moved from their disengaged position and separate means arranged to move the members and the contacts to their engaged position when the operable means is released to close the circuit, the said separate means operating until the held member is released and moved to its original position and its contact disengaged from the other contact.

7. An electric switch comprising a contact l and engagable with the rst contact to close a circuit but normally separated, the second contact member mounted on the first contact member and both members reciprocally movable relative to each other, a manually operable means to move the contactmembers simultaneously in one direction without the contacts engaging, a releasable means to hold one contact member in its reciprocated position and to be engaged by the other contact when the operable means is released to close a circuit, electrically controlled mechanism to trip the holding means when" current through the controlled mechanism reaches a predetermined value and spring means operating to move both contact members from their closed position to their formerly open position when release takes place.

EDGAR D. MOORE. 

